reorg code

.gitignore

@@ -0,0 +1 @@
+input

advent-of-code/2023/01/1.rkt → 01/1.rkt

@@ -1,6 +1,6 @@
 #lang racket
 
-(require "../../lib/utils.rkt")
+(require "../lib/utils.rkt")
 
 (define fp (open-input-file "input"))
 

advent-of-code/2023/01/2.rkt → 01/2.rkt

@@ -1,6 +1,6 @@
 #lang racket
 
-(require "../../lib/utils.rkt")
+(require "../lib/utils.rkt")
 
 (define fp (open-input-file "input"))
 

advent-of-code/2023/02/1.rkt → 02/1.rkt

@@ -1,6 +1,6 @@
 #lang racket
 
-(require "../../lib/utils.rkt")
+(require "../lib/utils.rkt")
 
 (define fp (open-input-file "input"))
 

advent-of-code/2023/02/2.rkt → 02/2.rkt

@@ -1,6 +1,6 @@
 #lang racket
 
-(require "../../lib/utils.rkt")
+(require "../lib/utils.rkt")
 
 (define fp (open-input-file "input"))
 

advent-of-code/2023/03/1.rkt → 03/1.rkt

@@ -1,7 +1,7 @@
 #lang racket
 
-(require "../../lib/utils.rkt")
-(require "../../lib/obj.rkt")
+(require "../lib/utils.rkt")
+(require "../lib/obj.rkt")
 
 (define (read-input)
   (call-with-input-file "input"

advent-of-code/2023/03/2.rkt → 03/2.rkt

@@ -1,7 +1,7 @@
 #lang racket
 
-(require "../../lib/utils.rkt")
-(require "../../lib/obj.rkt")
+(require "../lib/utils.rkt")
+(require "../lib/obj.rkt")
 
 (define (read-input)
   (call-with-input-file "input"

advent-of-code/2023/04/1.rkt → 04/1.rkt

@@ -1,7 +1,7 @@
 #lang racket
 
-(require "../../lib/utils.rkt")
-(require "../../lib/obj.rkt")
+(require "../lib/utils.rkt")
+(require "../lib/obj.rkt")
 
 (define fp (open-input-file "input"))
 

advent-of-code/2023/04/2.rkt → 04/2.rkt

@@ -1,7 +1,7 @@
 #lang racket
 
-(require "../../lib/utils.rkt")
-(require "../../lib/obj.rkt")
+(require "../lib/utils.rkt")
+(require "../lib/obj.rkt")
 
 (define fp (open-input-file "input"))
 

advent-of-code/2023/08/1.rkt → 08/1.rkt

@@ -1,6 +1,6 @@
 #lang racket
 
-(require "../../lib/utils.rkt")
+(require "../lib/utils.rkt")
 
 (define lines
   (call-with-input-file "input"

advent-of-code/2023/08/2.rkt → 08/2.rkt

@@ -1,6 +1,6 @@
 #lang racket
 
-(require "../../lib/utils.rkt")
+(require "../lib/utils.rkt")
 
 (define lines
   (call-with-input-file "input"

advent-of-code/2023/09/1.rkt → 09/1.rkt

@@ -1,6 +1,6 @@
 #lang racket
 
-(require "../../lib/utils.rkt")
+(require "../lib/utils.rkt")
 
 (define lines
   (call-with-input-file "input"

advent-of-code/2023/09/2.rkt → 09/2.rkt

@@ -1,6 +1,6 @@
 #lang racket
 
-(require "../../lib/utils.rkt")
+(require "../lib/utils.rkt")
 
 (define lines
   (call-with-input-file "input"

advent-of-code/2023/10/1.rkt → 10/1.rkt

@@ -1,6 +1,6 @@
 #lang racket
 
-(require "../../lib/utils.rkt")
+(require "../lib/utils.rkt")
 
 (define lines
   (call-with-input-file "input"

advent-of-code/2023/10/2.rkt → 10/2.rkt

@@ -1,6 +1,6 @@
 #lang racket
 
-(require "../../lib/utils.rkt")
+(require "../lib/utils.rkt")
 
 (define lines
   (call-with-input-file "input"

README.md

@@ -1,3 +1,3 @@
-# Practice
+# Advent of Code 2023 in Racket
 
-This code repository is the records of my solutions to problems on websites such as Advent of Code and CodeWars. Many of the problems are at the beginner level, so this code repository may have limited utility for others.
+My solutions of [Advent of Code 2023](https://adventofcode.com/2023) in [Racket](https://racket-lang.org/).

advent-of-code/2023/.gitignore

@@ -1 +0,0 @@
-input

codewars/6-kyu/pyramid-array/solution.rkt

@@ -1,14 +0,0 @@
-#lang racket
-
-;; https://www.codewars.com/kata/515f51d438015969f7000013
-
-(provide pyramid)
-
-(define (pyramid n)
-  (define (loop ret level cur)
-    (define next (cons 1 cur))
-    (if (= level n)
-        (reverse ret)
-        (loop (cons next ret) (+ level 1) next)))
-  (loop '() 0 '()))
-

codewars/7-kyu/a-rule-of-divisibility-by-7/solution.rkt

@@ -1,15 +0,0 @@
-#lang racket
-
-;; https://www.codewars.com/kata/55e6f5e58f7817808e00002e
-
-(provide seven)
-
-(define (seven m)
-  (define (impl cur steps)
-    (define x (quotient cur 10))
-    (define y (modulo cur 10))
-    (define next (- x (* 2 y)))
-    (if (< cur 100)
-        (cons cur steps)
-        (impl next (+ 1 steps))))
-  (impl m 0))

leetcode/1-two-sum/solution.rkt

@@ -1,16 +0,0 @@
-#lang racket
-
-;; https://leetcode.com/problems/two-sum/description/
-
-(define/contract (two-sum nums target)
-  (-> (listof exact-integer?) exact-integer? (listof exact-integer?))
-  (define h (make-hash))
-  (define (loop nums index)
-    (define n (car nums))
-    (define diff (- target n))
-    (if (hash-has-key? h diff)
-        (list index (hash-ref h diff))
-        (let ()
-            (hash-set! h n index)
-            (loop (cdr nums) (+ 1 index)))))
-  (loop nums 0))

leetcode/20-valid-parentheses/solution.rkt

@@ -1,33 +0,0 @@
-#lang racket
-
-;; https://leetcode.com/problems/valid-parentheses/
-
-(define (is-left-paren c)
-    (or (eq? c #\u28)
-        (eq? c #\[)
-        (eq? c #\{)))
-
-(define (right-paren c)
-    (cond ((eq? c #\u28) #\u29)
-          ((eq? c #\[) #\])
-          ((eq? c #\{) #\})))
-
-(define/contract (is-valid s)
-  (-> string? boolean?)
-  (define (loop s stack)
-    (if (= 0 (string-length s))
-        (null? stack)
-        (let ()
-            (define c (string-ref s 0))
-            (define remain (substring s 1))
-            (if (is-left-paren c)
-                (loop remain (cons c stack))
-                (if (null? stack)
-                    #f
-                    (let ()
-                        (define stack-top (car stack))
-                        (if (eq? c (right-paren stack-top))
-                            (loop remain (cdr stack))
-                            #f)))))))
-  (loop s '()))
-